title: A novel mitogen-activated protein kinase phosphatase-1 and glucocorticoid receptor (GR) interacting protein-1-dependent combinatorial mechanism of gene transrepression by GR.
abstract: Glucocorticoids have major antiinflammatory effects. Because COX-2 is the rate-limiting enzyme for proinflammatory prostaglandins, this study investigated the combinatorial inhibitory role of glucocorticoid receptor (GR) in COX-2 gene induction in macrophages and sought to identify the molecular mechanisms for that inhibition. Glucocorticoid-activated GR repressed COX-2 gene induction by lipopolysaccharide (LPS). Activated GR inhibited LPS-induced activator protein 1 activity, which in turn decreased activating transcription factor 2/c-Jun phosphorylation. The inhibition of MAPK-dependent activating transcription factor 2/c-Jun phosphorylation by GR in COX-2 repression was a result of MAPK phosphatase-1 (MKP-1) induction. Although GR did not inhibit LPS-induced p65 phosphorylation or nuclear factor-kappaB DNA binding activity, deletion of the nuclear factor-kappaB binding site in the COX-2 gene suppressed the ability of glucocorticoid to attenuate COX-2 induction. Chromatin immunoprecipitation and transfection assays revealed that a p65 DNA complex involving GR-bound GR-interacting protein 1 (GRIP1) also contributed to COX-2 repression. Additional knockdown and transfection assays identified other inflammatory genes coordinately regulated by MKP-1 and GRIP1. In summary, activated GR was found to antagonize the LPS-dependent induction of the COX-2 gene via a novel combinatorial mechanism involving MKP-1-mediated activator protein 1 inhibition and GR/GRIP1 recruitment to the p65 DNA complex; moreover, this work facilitated the identification of other GR-responding MKP-1/GRIP1-regulated genes.
authors.affiliation: Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy, Seoul National University, Sillim-dong, Kwanak-gu, Seoul 151-742, Korea.
authors.forename: Il Je
authors.initials: IJ
authors.lastname: Cho
authors.forename: Sang Geon
authors.initials: SG
authors.lastname: Kim
mesh_terms: D051698:Activating Transcription Factor 2 / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D004247:DNA / Q000235:genetics / Q000378:metabolism; D054638:Dual Specificity Phosphatase 1 / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D015870:Gene Expression; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D046911:Macromolecular Substances; D051379:Mice; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D051698:Activating Transcription Factor 2; D048868:Adaptor Proteins, Signal Transducing; C497106:Atf2 protein, mouse; C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; C491309:Grip1 protein, mouse; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; D016755:Proto-Oncogene Proteins c-jun; D011965:Receptors, Glucocorticoid; C498144:Rela protein, mouse; D051996:Transcription Factor RelA; D004247:DNA; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse